Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Survey on Defects Introduced by Flash Sintering Process" By Bo Yang Purdue MSE Preliminary Exam Advisor: Professor Xinghang Zhang ABSTRACT Flash sintering is a novel sintering technique utilizing external electric field to densify ceramic green body to near full density within a few seconds. The required furnace temperature is typically lower than the conventional sintering technique. The short dwell time and low sintering temperature can dramatically cut down the energy consumption and enable fabrication of ultra-fine grain structure. Ever since first reported in 2010, flash sintering has been widely studied among many ceramic systems. However, a general mechanism explaining the rapid densification rate has not yet been identified. Currently, two competing hypotheses, (1) fast densification rate due to Joule heating, and (2) enhanced diffusion coefficient due to the avalanche of point defects, are under debate. This report summarizes some major findings on the defects induced in numerous flash sintered ceramics. One predominant defect is oxygen vacancy that may play an important role during the onset of flash sintering. In addition, other types of defects, such as dislocations, stacking faults, and secondary phases, have been reported. The nature of defects and their nucleation sites vary among different ceramic systems. Despite a large number of reports covering flash sintering of ceramics, the in-depth understanding on the correlation between possible flash sintering mechanisms and resultant microstructures remains limited. More systematic microstructural studies should be conducted to identify the connection between defects and flash sintering mechanisms. Date: Wednesday, October 23, 2019 Time: 8:30 A.M. Place: ARMS 1021